[PATCH 5/8] iommu/vt-d: Use intel_pasid_write() for first-stage setup

[Lu Baolu]

Refactor intel_pasid_setup_first_level() to utilize the intel_pasid_write()
helper. By moving to the entry_sync library, the driver now constructs the
target entry in a local buffer and hands it off to intel_pasid_write().

This refactoring removes the need for __domain_setup_first_level(),
simplifies locking by using the group mutex, and ensures a consistent
update path for all first-stage setups.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel/iommu.h |  5 -----
 drivers/iommu/intel/iommu.c | 16 +++-------------
 drivers/iommu/intel/pasid.c | 36 +++++++++---------------------------
 drivers/iommu/intel/svm.c   |  5 ++---
 4 files changed, 14 insertions(+), 48 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 54b58d01d0cb..fd6ca3b7f594 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1202,11 +1202,6 @@ domain_add_dev_pasid(struct iommu_domain *domain,
 		     struct device *dev, ioasid_t pasid);
 void domain_remove_dev_pasid(struct iommu_domain *domain,
 			     struct device *dev, ioasid_t pasid);
-
-int __domain_setup_first_level(struct intel_iommu *iommu, struct device *dev,
-			       ioasid_t pasid, u16 did, phys_addr_t fsptptr,
-			       int flags, struct iommu_domain *old);
-
 int dmar_ir_support(void);
 
 void iommu_flush_write_buffer(struct intel_iommu *iommu);
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5369526e89d0..db5e8dad50dc 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1248,16 +1248,6 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8
 	__iommu_flush_cache(iommu, context, sizeof(*context));
 }
 
-int __domain_setup_first_level(struct intel_iommu *iommu, struct device *dev,
-			       ioasid_t pasid, u16 did, phys_addr_t fsptptr,
-			       int flags, struct iommu_domain *old)
-{
-	if (old)
-		intel_pasid_tear_down_entry(iommu, dev, pasid, false);
-
-	return intel_pasid_setup_first_level(iommu, dev, fsptptr, pasid, did, flags);
-}
-
 static int domain_setup_second_level(struct intel_iommu *iommu,
 				     struct dmar_domain *domain,
 				     struct device *dev, ioasid_t pasid,
@@ -1301,9 +1291,9 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
 	      BIT(PT_FEAT_DMA_INCOHERENT)))
 		flags |= PASID_FLAG_PWSNP;
 
-	return __domain_setup_first_level(iommu, dev, pasid,
-					  domain_id_iommu(domain, iommu),
-					  pt_info.gcr3_pt, flags, old);
+	return intel_pasid_setup_first_level(iommu, dev, pt_info.gcr3_pt, pasid,
+					     domain_id_iommu(domain, iommu),
+					     flags);
 }
 
 static int dmar_domain_attach_device(struct dmar_domain *domain,
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index b7c8888afaef..8ea1ac8cbf5e 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -172,9 +172,8 @@ static const struct entry_sync_writer_ops128 writer_ops128 = {
 
 #define INTEL_PASID_SYNC_MEM_COUNT	12
 
-static int __maybe_unused intel_pasid_write(struct intel_iommu *iommu,
-					    struct device *dev, u32 pasid,
-					    u128 *target)
+static int intel_pasid_write(struct intel_iommu *iommu, struct device *dev,
+			     u32 pasid, u128 *target)
 {
 	struct pasid_entry *pte = intel_pasid_get_entry(dev, pasid);
 	struct intel_pasid_writer p_writer = {
@@ -531,17 +530,14 @@ static void intel_pasid_flush_present(struct intel_iommu *iommu,
 
 /*
  * Set up the scalable mode pasid table entry for first only
- * translation type.
+ * translation type. Caller should zero out the entry before
+ * calling.
  */
 static void pasid_pte_config_first_level(struct intel_iommu *iommu,
 					 struct pasid_entry *pte,
 					 phys_addr_t fsptptr, u16 did,
 					 int flags)
 {
-	lockdep_assert_held(&iommu->lock);
-
-	pasid_clear_entry(pte);
-
 	/* Setup the first level page table pointer: */
 	pasid_set_flptr(pte, fsptptr);
 
@@ -564,7 +560,9 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu, struct device *dev,
 				  phys_addr_t fsptptr, u32 pasid, u16 did,
 				  int flags)
 {
-	struct pasid_entry *pte;
+	struct pasid_entry new_pte = {0};
+
+	iommu_group_mutex_assert(dev);
 
 	if (!ecap_flts(iommu->ecap)) {
 		pr_err("No first level translation support on %s\n",
@@ -578,25 +576,9 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu, struct device *dev,
 		return -EINVAL;
 	}
 
-	spin_lock(&iommu->lock);
-	pte = intel_pasid_get_entry(dev, pasid);
-	if (!pte) {
-		spin_unlock(&iommu->lock);
-		return -ENODEV;
-	}
+	pasid_pte_config_first_level(iommu, &new_pte, fsptptr, did, flags);
 
-	if (pasid_pte_is_present(pte)) {
-		spin_unlock(&iommu->lock);
-		return -EBUSY;
-	}
-
-	pasid_pte_config_first_level(iommu, pte, fsptptr, did, flags);
-
-	spin_unlock(&iommu->lock);
-
-	pasid_flush_caches(iommu, pte, pasid, did);
-
-	return 0;
+	return intel_pasid_write(iommu, dev, pasid, (u128 *)&new_pte);
 }
 
 /*
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index fea10acd4f02..978d63073e3b 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -171,9 +171,8 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 	/* Setup the pasid table: */
 	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
 	sflags |= PASID_FLAG_PWSNP;
-	ret = __domain_setup_first_level(iommu, dev, pasid,
-					 FLPT_DEFAULT_DID, __pa(mm->pgd),
-					 sflags, old);
+	ret = intel_pasid_setup_first_level(iommu, dev, __pa(mm->pgd),
+					    pasid, FLPT_DEFAULT_DID, sflags);
 	if (ret)
 		goto out_unwind_iopf;
 
-- 
2.43.0